SPONTANEOUS ADSORPTION OF HETEROPOLYTUNGSTATES AND HETEROPOLYMOLYBDATES ON THE SURFACES OF SOLID ELECTRODES AND THE ELECTROCATALYTIC ACTIVITY OF THE ADSORBED ANIONS

Heteropolytungstate and heteropolymolybdate anions spontaneously adsor b from aqueous solutions onto mercury, gold, pyrolytic graphite and gl assy carbon electrodes. The adsorption persists when the electrodes ar e transferred to pure supporting electrolyte solutions where the elect rochemical responses from the adsorbed anions can be observed. The ads orption is much less extensive from non-aqueous solvents. The adsorbed anions can serve as catalysts for various electrode reactions. Exampl es are given of the electrocatalytic reductions of hydrogen peroxide t o water and of nitrite to ammonia.